/*
 * This program is free software: you can redistribute it and/or modify it under
 * the terms of the GNU General Public License as published by the Free Software
 * Foundation, either version 3 of the License, or (at your option) any later
 * version.
 * 
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
 * FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
 * details.
 * 
 * You should have received a copy of the GNU General Public License along with
 * this program. If not, see <http://www.gnu.org/licenses/>.
 */
package net.sf.l2j;

import java.sql.Connection;
import java.sql.SQLException;
import java.util.logging.Level;
import java.util.logging.Logger;

import com.mchange.v2.c3p0.ComboPooledDataSource;

public class L2DatabaseFactory
{
    static Logger _log = Logger.getLogger(L2DatabaseFactory.class.getName());

    public static enum ProviderType
    {
        MySql,
        MsSql
    }

    // =========================================================
    // Data Field
    private static L2DatabaseFactory _instance;
    private ProviderType _providerType;
	private ComboPooledDataSource _source;

    // =========================================================
    // Constructor
	public L2DatabaseFactory() throws SQLException
	{
		try
		{
			if (Config.DATABASE_MAX_CONNECTIONS < 2)
            {
                Config.DATABASE_MAX_CONNECTIONS = 2;
                _log.warning("A minimum of " + Config.DATABASE_MAX_CONNECTIONS + " db connections are required.");
            }

			_source = new ComboPooledDataSource();
			_source.setAutoCommitOnClose(true);

			_source.setInitialPoolSize(10);
			_source.setMinPoolSize(10);
			_source.setMaxPoolSize(Math.max(10, Config.DATABASE_MAX_CONNECTIONS));


			_source.setAcquireRetryAttempts(0); // try to obtain connections indefinitely (0 = never quit)
			_source.setAcquireRetryDelay(500);  // 500 milliseconds wait before try to acquire connection again
			_source.setCheckoutTimeout(0);      // 0 = wait indefinitely for new connection
			// if pool is exhausted
			_source.setAcquireIncrement(5);     // if pool is exhausted, get 5 more connections at a time
			// cause there is a "long" delay on acquire connection
			// so taking more than one connection at once will make connection pooling
			// more effective.

			// this "connection_test_table" is automatically created if not already there
			_source.setAutomaticTestTable("connection_test_table");
			_source.setTestConnectionOnCheckin(false);

			// testing OnCheckin used with IdleConnectionTestPeriod is faster than  testing on checkout

			_source.setIdleConnectionTestPeriod(3600); // test idle connection every 60 sec
			_source.setMaxIdleTime(Config.DATABASE_MAX_IDLE_TIME); // 0 = idle connections never expire
			// *THANKS* to connection testing configured above
			// but I prefer to disconnect all connections not used
			// for more than 1 hour

			// enables statement caching,  there is a "semi-bug" in c3p0 0.9.0 but in 0.9.0.2 and later it's fixed
			_source.setMaxStatementsPerConnection(100);

			_source.setBreakAfterAcquireFailure(false);  // never fail if any way possible
			// setting this to true will make
			// c3p0 "crash" and refuse to work
			// till restart thus making acquire
			// errors "FATAL" ... we don't want that
			// it should be possible to recover
			_source.setDriverClass(Config.DATABASE_DRIVER);
			_source.setJdbcUrl(Config.DATABASE_URL);
			_source.setUser(Config.DATABASE_LOGIN);
			_source.setPassword(Config.DATABASE_PASSWORD);

			/* Test the connection */
			_source.getConnection().close();

			if (Config.DEBUG) _log.fine("Database Connection Working");

			if (Config.DATABASE_DRIVER.toLowerCase().contains("microsoft"))
                _providerType = ProviderType.MsSql;
            else
                _providerType = ProviderType.MySql;
		}
		catch (SQLException x)
		{
			if (Config.DEBUG) _log.fine("Database Connection FAILED");
			// re-throw the exception
			throw x;
		}
		catch (Exception e)
		{
			if (Config.DEBUG) _log.fine("Database Connection FAILED");
			throw new SQLException("could not init DB connection:"+e);
		}
	}

    // =========================================================
    // Method - Public
    public final String prepQuerySelect(String[] fields, String tableName, String whereClause, boolean returnOnlyTopRecord)
    {
        String msSqlTop1 = "";
        String mySqlTop1 = "";
        if (returnOnlyTopRecord)
        {
            if (getProviderType() == ProviderType.MsSql) msSqlTop1 = " Top 1 ";
            if (getProviderType() == ProviderType.MySql) mySqlTop1 = " Limit 1 ";
        }
        String query = "SELECT " + msSqlTop1 + safetyString(fields) + " FROM " + tableName + " WHERE " + whereClause + mySqlTop1;
        return query;
    }

    public void shutdown()
    {
        try {
            _source.close();
        } catch (Exception e) {_log.log(Level.INFO, "", e);}
        try {
            _source = null;
        } catch (Exception e) {_log.log(Level.INFO, "", e);}
    }

    public final String safetyString(String... whatToCheck)
    {
        // NOTE: Use brace as a safty precaution just incase name is a reserved word
        final char braceLeft;
        final char braceRight;
        
        if (getProviderType() == ProviderType.MsSql) {
            braceLeft = '[';
            braceRight = ']';
        } else {
            braceLeft = '`';
            braceRight = '`';
        }

        int length = 0;
        
        for (String word : whatToCheck) {
            length += word.length() + 4;
        }

        final StringBuilder sbResult = new StringBuilder(length);
        
        for(String word : whatToCheck)
        {
            if (sbResult.length() > 0) {
                sbResult.append(", ");
            }

            sbResult.append(braceLeft);
            sbResult.append(word);
            sbResult.append(braceRight);
        }
        
        return sbResult.toString();
    }

    // =========================================================
    // Property - Public
	public static L2DatabaseFactory getInstance() throws SQLException
	{
		if (_instance == null)
		{
			_instance = new L2DatabaseFactory();
		}
		return _instance;
	}

	public Connection getConnection() //throws SQLException
	{
		Connection con=null;

		while(con==null)
		{
			try
			{
				con=_source.getConnection();
			} catch (SQLException e)
			{
				_log.warning("L2DatabaseFactory: getConnection() failed, trying again "+e);
			}
		}
		return con;
	}

	public int getBusyConnectionCount() throws SQLException
	{
	    return _source.getNumBusyConnectionsDefaultUser();
	}

	public int getIdleConnectionCount() throws SQLException
	{
	    return _source.getNumIdleConnectionsDefaultUser();
	}

    public final ProviderType getProviderType() { return _providerType; }
}
